The present invention disclosed herein relates to a dissolved oxygen measurement system, and more particularly, a dissolved oxygen measurement system, which measures dissolved oxygen in real-time using hydrogen generated using solar energy as an energy source.
The dissolved oxygen (DO) is the amount of oxygen that is dissolved in water, i.e., the amount of oxygen directly necessary for organisms that live in the water such as fishes and widely used as an indication of the quality of water.
The dissolved oxygen is influenced by a water temperature and the amount of microorganisms. Specifically, when microorganisms are introduced, oxygen is consumed by aerobic microorganisms to reduce the amount of oxygen dissolved in water (dissolved oxygen). Thus, the more the amount of microorganisms within water increases, the more consumption of oxygen is significantly increased. As a result, the amount of oxygen necessary for organisms living in the water may be significantly reduced to deteriorate the quality of water. Accordingly, the measurement of the amount of microorganisms can prevent a river from being contaminated. However, since it is difficult to directly measure the total microorganisms, oxygen within water taken from a river is measured, and then, oxygen consumed by microorganisms as time goes on is measured to predict some how many microorganisms there are.
For example, a method of measuring the amount of oxygen dissolved in water (dissolved oxygen) may include an electrochemical measurement method and a method using a pressure variation due to consumption of oxygen.
The method of electrochemically measuring a concentration of oxygen is a method in which a concentration of oxygen measured through electrochemical current is reduced when the amount of oxygen consumed by microorganisms is increased. This method may detect the oxygen concentration from the amount of current flowing through three electrodes that is used in a general cyclic voltammetry method. Also, according to the electrochemical measurement method, the amount of oxygen is analyzed by transmitting only oxygen and blocking liquid using a membrane through which only oxygen is filtered.
On the other hand, according to the method using the pressure variation, oxygen that can maintain a certain oxygen pressure is injected into water, and then, pressure reduction of oxygen is measured using a pressure sensor because the amount of initially injected oxygen is reduced according to the amount of oxygen consumed by microorganisms in water.
As described above, in the methods of measuring the oxygen concentration, the predetermined amount of water to be measured in a laboratory is taken to measure the amount of oxygen. Then, the taking water is cultivated in shady facility for about five days to measure again the amount of oxygen. Thereafter, biochemical oxygen demand (BOD) is determined by the difference between the amounts of oxygen measured in the two samples. However, in these oxygen concentration measurement methods, it is impossible to measure the dissolved oxygen in real time. That is, since taking water should be cultivated in a laboratory for about five days, it is impossible to measure the dissolved oxygen required to be quickly analyzed.